It's a stair case that gets steeper the higher you go. Thus the difference between 6.0 and 7.0 earthquakes is much greater than the difference between 3.0 and 4.0 earthquakes. The linked video discusses money, but the same principle applies to earthquakes.

METAMIA is a free database of analogy
and metaphor. Anyone can contribute or search.
The subject matter can be anything.
Science is popular, but poetry is encouraged.
The goal is to integrate our fluid muses with
the stark literalism of a relational database.
Metamia is like a girdle for your muses,
a cognitive girdle.